Sliding door



FIG. 1 is a front view of a sliding door;

FIG. 2 is a rear view thereof;

FIG. 3 is a side view thereof;

FIG. 4 is an opposite side view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The nature of the front and rear surfaces of the sliding door are that of a flat plane.

The broken line depictions form no part of the claimed design. 

CLAIM The ornamental design for a sliding door, as shown and described. 